Milwaukee Cobalt Drill Bit

The Milwaukee Cobalt Drill Bit, model 48-89-2312, is a tool that I had high hopes for given Milwaukee's reputation for quality and innovation in the tool industry. Designed specifically for hard metal applications, PVC, and wood, this drill bit boasts several features that promise durability and precision. After putting it through a series of rigorous tests, I have mixed feelings about its performance.

Design and Build Quality

The drill bit is made from cobalt alloy, which is intended to increase its lifespan compared to standard drill bits. The QUADEDGE TIP™ and the 135° split point are supposed to reduce heat build-up and improve drilling speed while ensuring accurate starting. The VARIABLE HELIX™ design is another interesting feature, aimed at efficient chip removal and preventing the bit from walking during use.

The bit also features a 3-Flat Secure-Grip™ to prevent slipping in the chuck, which I found to be particularly useful. The enhanced tapered web is designed to strengthen the core of the bit, adding to its durability. At first glance, the bit seems robust and well-engineered.

Performance on Different Materials

Hard Metals

My primary use for this bit was in drilling through various types of metal, including stainless steel and mild steel. I started with a piece of 3/16" thick hardened steel. The bit performed admirably, quickly creating holes without any visible signs of wear. The 135° split point worked as advertised, ensuring the bit didn't walk, and the VARIABLE HELIX™ design efficiently removed the chips.

However, the performance was inconsistent. On another occasion, I attempted to drill through a piece of 1/4" thick stainless steel. Despite using cutting oil and drilling at a slow speed, the bit dulled significantly after just a few holes. This was disappointing, considering the bit is marketed for hard metal applications. I also noticed that the bit generated a lot of heat despite the QUADEDGE TIP™ feature, which is supposed to minimize this issue.

PVC and Wood

Switching to PVC and wood, the bit performed exceptionally well. Drilling through PVC was effortless, and the bit maintained its edge without any noticeable wear. In wood, the bit was equally efficient. The holes were clean, and the bit didn't walk, thanks to the 135° split point. The VARIABLE HELIX™ design again proved effective in chip removal, making the drilling process smooth.

Durability and Edge Retention

Durability is where this bit's performance was most inconsistent. While it handled PVC and wood without any issues, my experience with metal was varied. The bit dulled quickly when used on thicker or harder metals, and in some cases, it even chipped. This was a significant letdown, especially given the bit's price point.

Ease of Use

One of the bit's standout features is its ease of use. The 3-Flat Secure-Grip™ design ensures that the bit doesn't slip in the chuck, providing a secure grip even during intense drilling sessions. The split point tip also makes it easy to start drilling without the bit walking, which is a common issue with other bits.

Value for Money

Given its inconsistent performance on metal, the value for money is questionable. While it excels in drilling through PVC and wood, its primary selling point is hard metal applications, where it falls short. The bit is priced higher than many other drill bits on the market, and its performance does not consistently justify the cost.

Customer Support

One aspect where Milwaukee shines is customer support. In instances where the bit failed prematurely, Milwaukee was quick to offer replacements. This level of customer service is commendable and somewhat offsets the bit's performance issues.

Final Thoughts

The Milwaukee Cobalt Drill Bit is a tool that excels in some areas but falls short in others. Its design and build quality are impressive, and it performs exceptionally well on PVC and wood. However, its inconsistent performance on hard metals, which is its primary selling point, is a significant drawback.

Would I recommend this tool? It depends on your needs. If you're primarily drilling through PVC and wood, this bit is a solid choice. Its ease of use, secure grip, and efficient chip removal make it a reliable tool for these materials. However, if you frequently work with hard metals, you may want to consider other options. The bit's durability and edge retention in these applications are inconsistent, and you might find yourself replacing it more often than expected.

In summary, while the Milwaukee Cobalt Drill Bit has its merits, it doesn't consistently live up to its promises for hard metal applications. For those specific needs, you might be better off exploring other high-quality options on the market.